Instructions

  1. In the microwave (I use my 8-cup Pyrex measuring cup for this) or on top of the stove (using a heavy-bottomed sauce pan) combine sugar, cornstarch, lemon zest, lemon juice, egg yolks, half and half and whipping cream (can use 2 cups half and half cream if desired and omit the whipping cream); whisk to combine.
  2. Microwave on HIGH until thick (removing about every minute to whisk/stir).
  3. Cook until thickened.
  4. Stir in butter; whisk until butter has melted and the mixture is smooth.
  5. Cool to almost room temperature, stirring every so often.
  6. Stir in sour cream until well blended.
  7. Divide evenly between baked tart shells.
  8. Top with a dollup of Cool Whip.
  9. Delicious!